Blackley, whom was acquired from the Oakland Athletics yesterday, will be with the Astros for tonight's game and will wear #54. He was 6-4 with a 4.10 ERA (49ER/107.2IP) in 28 games, including 15 starts, with San Francisco (4g) and Oakland (24g) last season.

Gonzalez, who has been with the Astros since last season, did not appear in the first three games of the 2013 season. The Astros 40-man roster is now at 40.

WHITE TO HAVE ELBOW SURGERY

Luhnow also announced today that right-handed pitcher Alex White will undergo ulnar collateral ligament reconstruction surgery (Tommy John) on his right elbow next week. White left his last start on Friday (3/29) vs. the Cubs after experiencing discomfort in his right elbow.